Pulled in the drive the other night Cold, Rain, dark so I had everything turned on) and turned off my headlights and they didn't go down. OK no big deal replace the fuse. (BLINK)... Where to go from here??? Checked all bulbs and I mean all bulbs, do you know how many bulbs are in the back end of an 86GT?? Well in an effort to try and isolate my problem I unplugged the big plug inside my tunk by the brake unit. Put in a fuse and it seemed OK. Well I plugged it back in and headlights go down. So maybe its fixed?? WRONG!
Turn on headlights they come on and go up taillights work, all works till I turn off the headlights. Dash lights go off headlights dim but don't go off and they do not go down. If I pull the taillight fuse the headlights go off, then reinsert the fuse and the headlights go down.
I purchased a new relay and tried changing it out with the three in there. Now by reading old posts here I find out there are 2 types of relays in the system that are not interchangeable???
Now I replace the fuse, turn on headlights and start for work, (BLINK) there goes the fuse, dash lights go off as well as tail lights.
The car is an 86GT automatic all options except rear window defogger.
Anyone have any ideas other than finding another car???

Amlost anytime you blow fuses like this there is a bad ground or most likely short somewhere in the system. Don't get another car....if this is a new problem just try to think about what has changed that could cause a short in the electrical system. Start from the front of the car and trace the wiring trying to find a bad wire or ground.

I know that this is not the answer you are looking for but without inspecting the system myself it is hard to tell what the problem is.

i agree, many times the problem can be a faulty ground. you may also want to check the fuse boxm itself. sometimes junctions can become seporated, or knocked lose (especially if you have several aftermarket options on the car). you may also want to check the switch for the lights, it may need cleaning or replacing.

Sounds like a short to ground in the power side of your lights system.Headlights and taillights are probably on the same circuit.It could even be a bad ground off the bulbs.Disconnect one bulb at a time and try to notice any difference.Connections to
bulbs,and try the back bulbs,one at a time first.Keep us posted.I can get you there.

Tried a different headlight switch, didn't change anything. Pulled tested & reinstalled all fuses, no change.
Can anyone identify the major locations of the ground wire connections? One is located on the fenderwell side left side of the left headlight.
This is a real pain!

Yo Dog, give it a try. We can get you thru this.

Still fighting?
Getting closer I think. I unplugged the connector by the battery and seperated it so I can plug in either half. When I plug in the half that goes on to the tail lights my problem shows up. So I moved, twisted and pulled on those wires, even tightened ground above right rear wheel (you have to remove inner fender to get to it) Problem still there?? Removed tail lights and one bulb at a time still have problem. Where to go from here??
First I think I should invest in a fuse company!

sounds like a pinched wire in the tail light harness. maybe a bad socket.